What is the 'part-payment' rule and how might the decision in Williams v Roffey affect it? What did the court in Re Selectmove say about this and why do academics differ on this issue? Contrast, for example, the views set out in J Adams & R Brownsword, 'Contract, Consideration and the Critical Path' (1990) 53 MLR 536 with J O'Sullivan, 'In Defence of Foakes v Beer' [1996] CLJ 219